Abstract: This unusual complexometric procedure is successfully applied in the determination of uranium. Optimum conditions for quantitative reduction of U(Ⅵ) to U(Ⅳ) by Na2S2O4 are investigated. The relative standard deviation for the determination of 2 micrograms of uranium is less than ±1%, while that for 4 micrograms of uranium is less than±0.5%. The results of uranium in two standard uranium ore samples using TBP-levextrel presepara-tion show that both accuracy and precision are within 0.5%.